Heating system



H. B. HOLTHOUSE HEATING SYSTEM Filed Jan. 19, 1942 3 Sheets-Sheet 1 Oct. 2, 1945.

H. B. HOLTHOUSE 2,386,115

HEATING SYSTEM Filed Jan. 19, 1942 s Sheets-sheaf 2 Patented Oct. 2, 1945 HEATING SYSTEM Harry B. Holthouse, Chicago, 111., assignor to Galvin Manufacturing Corporation, Chicago,

lll., a corporation of Illinois Application January 19, 1942: Serial No. 427,355

8 Claims.

This invention relates generally to air heating systems and in particular to a portable self-contained heating system of unit type adapted to be operated when supported on a horizontal surface or suspended from a single point thereon.

It is an object of this invention to provide an improved air heating system. i

Another object of this invention is to provide an air heating system of unit type which can be readily transferred from place to 'place and operl ated when suspended.

Yet another object of this invention is to provide a heating system of unit type for individually heating airplane engines for starting purposes which can be suspended in close proximity to the engine, or supported on any suitable horizontal surface adjacent the engine or cooling air passage leading thereto.

A still further object of this invention is to provide a heating system of unit type which is simple in desi n. r gged in construction, and comprised of a minimum number of parts, and adapted for efficient operation over a prolonged service life with minimum servicing attention.

A particular feature of this invention is found 2 in the provision of a self-contained heating system of internal combustion type which is fully-enclosed and transportable as a complete package, and capable of operation when supported on the ground or suspended from a single point thereon. When'o'perated on the ground or other horizontal supporting surface the unit is of such a construction that a plurality of the units may be arranged in asuperposed relation with each thereof operating independently of the other.

Further objects, features and advantages of this invention will become apparent from the follow-'- ing description when taken in connection with the accompanying drawings in'which:

Fig. 1 is a front perspective view showing the complete heating unit of this invention:

Fig. 2 is a diagrammatic illustration of a control circuit for the heating unit of Fig. 1':

Fig. 3 is a transverse sectional view of the heater unit;

- Fig. 4 shows a plurality of the heating units arrangedinasuperposed relation:

Fig. 5 is a perspective view of an adjustable strap by which the heating unit of Fig. 1 may be suspended; 1

Fi 6 ma sectional detail view of a fuel conditioning unit utilized in the heater of this invention;

Fig. '7 is a longitudinal sectional view taken approximately along the line 1-4 in Fig. 3, the

showing of the combustion chamber for the heating unit being somewhat of a developed view;

Fig. 8 shows the application of the heating unit in a horizontally suspended position for heating an airplane engine; and

Fig. 9 shows the application of the heating unit in a horizontally-supported position for heatiiis an airplane engine.

In practicing this invention, there is provided a package air heating unit of internal combustion type which includes a gravity feed fuel system and an electrical motor for operating fans for supplying air for combustion, and for circulating the air to be heated in thermal re1ationwith the combustion chamber. The unit is fully'enclosed. and is provided with electrical sockets thereon which are readily accessible for connecting the motor with a suitable source of electrical supply, such as a power line or an engine-generator set. For suspending the 'unit in an operating position, a single suspension is provided at the top thereof which also serves as a handle for carrying the unit about. The outlet for the heated ,air passage has an angularly adjustable nozzle thereon so that the heated air may be directed in any one of a plurality of directions. A manually actuated 1 control switch for the fan motor is operatively associated withfa fuel valve in the fuel system in a manner such that fuel is admitted to the heater. combustion chamber only after the motor is in operation. By virtue of the unit be g self-contained and capable of being opera when supported on a horizontal surface or when m nded. it may be readily positioned in close proximity to the space to be heated regardless of the location of such space This flexibility in positioning the l heater of this invention for operation has been found particularly useful in the heating of air-- plane engines for starting pu p ses.

Referring to the drawings, the heating unit I! is shown in Figs. 1, 3 and Les having frame means designated generally as It and including horizontally extending supporting members I1 and I. of substantially rectangular shape. The members ii and I8 are vertically spaced apart in a parallel relation by a substantially U-shaped connecting member ll having leg portions 2i and 22 rigidly secured to the supporting members II and l8, respectively, with the connecting portion 2| between the leg portions 2| and 22 being'vertical and extended longitudinally ofv the supporting members i1 and I8 and hence of the heatin! unit. An open frame or housing member 23 of a rectangular shape corresponding to the shape of the supporting members ll and i8 is positioned about the frame means i3 so as to enclose the space between the supporting members I! and i8 and forms closed compartments or chambers 24 and 23 to each side of the vertical portion 23 of the connecting member IS. The frame 23 is scoured as by screws 23 to laterally bent flange portions 21 and 28 integrally formed with the supporting members I! and I8, respectively. Be.- cause of the flange portions 21 it is seen that the supporting member I! is spaced upwardly from the lower end of the heating unit i for a purpose to be noted later.

Arranged within the compartment 24 are a motor 3|, a fuel sump 32 and a fuel metering device 33 arranged in a fuel line 34 connecting the sump with a fuel nozzle 38. Also located in the compartment 24 is a valve unit 31 connected in the fuel line 34 between the sump 32 and metering device 33, and having a valve stem 38 projecting outwardly from the housing member 23. A control knob 33 is carried on the projecting end .of the stem 38. The valve stem 33 has a cam 4| mounted thereon within the compartment 24 for operating a control switch 42 for the motor 3| concurrently with the operation of the fuel valve 31. The chamber 24 is in open communication with a fan chamber 43 having a fan 44 therein mounted on the shaft 43 of the motor 3|. The fan chamber 43 (Fig. 7) is fluid connected with an annular air passage 41 formed about a combustion chamber 48 located in the compartment 23 and which will be later explained. The fan 33 functions to circulate air to be heated through the passage 41 in thermal relation with the combustion chamber and discharges the same through an outlet 43 in the side 5| of the frame member 23, the outlet 48 being open to the compartment 23. The air for the fan 44 is supplied'through an inlet 52 also located in the housing side 3| but opening into the compartment 33. A screen 33 is extended over the inlet 52 to filter the air passthe combustion chamber 43 as viewed in Fig. 7.

The annular passage 41 is separated from the air supply chamber 33, and chamber 33 for the fan 53 by a partition member 33 which is positioned transversely of the heating unit is and has an opening 3| therein for. receiving a sleeve member 32. The sleeve mem er 32 is extended axially from the combustion chamber 38 but is separated therefrom by a plate member 33. The sleeve member 32 and partition member 33 thus separate the chambers 53 and 33 from the annular passage 31- and chamber 33 for the fan 34. The air from the supply chamber 53 is mixed with the fuel from the fuel nozzle 33 in a fuel conditioning unit 34 which is located in the chamber 33 at the inlet 33 of the combustion chamber 43 and will be later described.

The combustion chamber 43 extends longitudinally of the heater unit i3 and has an outer cylindrical casing 31 (Fig. 3) which is suitably secured to the connecting member IS. The combustion chamber 43 includes a tubular body member 33 of unit construction integrally formed with alternate peripheral sections 38 and radially extending fin elements 33. The fin elements 33 are bent double so that their inner ends are open to the bore or space within the tubular member 38. The

member'33. The casing 31, previously mentioned,

is positioned about the fins and with the member 33 forms that portion of the passage 31 about the combustion chamber, the fins 69 extending into such passage portion. The heat transferred to the fins 33 is radiated to the air flowing through the passage 41 to heat the same.

The mixture from the fuel conditioning unit 34 passes progressively through the combustion chamber passages I |a-'| Id and is exhausted from the heater through a tail-pipe assembly, indicatedgenerally as I3, whichis connected with the combustion chamber outlet 14 in the plate member 33. By virtue of this construction of the combustion chamber 33 the inlet 33 and outlet #4 thereof are both located in the plate 33, the exhaust gases being passed from the heater unit through the side 33 thereof.

The fuel conditioning unit 34, shown in detail in Fig. 6, includes a substantially tubular shaped housing ll closed at one end I8 and open at its opposite or outlet end i3 for fluid connection with the combustion chamber passa e Ila. The closed end 18 of the conditioning unit. (Fig. '7) extends into the air supply chamber 53. The housing member TI is provided in a high heat conductingmaterial and includes an air and fuel mixing chamber 8| at the closed end thereof and an equalizing chamber 82 adJacent thereto. the mixing chamber 3| and equalizing chamber 32 being separated by a heat conducting partition plate 83 having perforations 34 over the upper portion thereof. The equalizing chamber 82 in turn is separated from the combustion chamber passage Ila by a heat insulating plate 33 having perforations 31 arranged peripherally therein. Positioned axially through the housing member I1 and supported in the housing end 13 and partition plates 83 and 83 isan electrical heating unit 83. The heating unit 33 comprises a tubular shell 33 having a resistance wire 3| therein extending over that portion of the tube 33 within the mixing and equalizing chambers.

. The fuel injection nozzle 33 is mounted at the closed end 13 of the conditioning unit 33 and is positioned within the air supply chamber 53. The nozzle 33 is formed with air ports or apertures 92 for admitting air from the air chamber 53 into the fuel stream within the injector. Additional air is supplied to the mixing chamber 8| directly from the air chamber 33 through openings 33 formed in the closed end of the housing 13 and about the fuel injection nozzle 33. During the normal operation of the heater the fuel admitted into the mixing chamber 3| from the nozzle 33 is directed against that portion of the copper tube 83 within the mixing chamber 3| and against the walls of the mixing chamber. Because of the high heat conductivity of the housing II and its thermal connection with the partition plate 34 and copper tube 89 these parts are readily heated on energization of the resistance 3| to at least a fuel vaporizing temperature.

The vaporization of the fuel in the mixing chamber 8| facilitates its'being mixed together with the air supplied to the mixing chamber so that a substantially complete vaporous air and fuel mixture passes into the equalizing chamber 82 through the perforations 84 in the plate 83. -The equalizing chamber 82 functions to reduce the degree of turbulence in the mixture and with the plate 86 serves to disperse the same substantially uniformly over the cross-sectional area of the conditioning unit outlet 19. A mixture of substantially uniform fuel density is thus admitted for burning into the combustion chamber 48, the combustion of the mixture being initiated by the passage of the mixture about the end 94 of the resistance 9|, the degree of theignition heat at the end 84 being determined essentially by the watt input to the resistance 9|.

The fuel to be burned in the combustion chamber 48 is supplied from a fuel tank 98 (Figs. 1 and 3) which is of rectangular box shap and carried on the supporting member I8 in a superposed relation. Extended vertically through the tank 96 are symmetrically or rectangularly arranged tubes 91 which are aligned with corresponding nuts 88 'secured to the underside of the supporting member I8. The tubes 91 terminate in the sides of the tank 96 and are suitably brazed or welded thereto so as to prevent any leakage of fuel from the tank at these points. Studs or bolts 99 having a headed portion at one end and a threaded portion at the opposite end are inserted within corresponding tubes 91, the threading of a stud 99 within a corresponding nut 98 rigidly securing the tank 98 to the frame means I6 in an obvious manner. The fuel sump 32 is fluid connected with the tank 93 through connecting means III I With the heating unit I in a horizontal position there is thus provided a gravity feedfuel system for the heating unit, with the fuel admitted to the conditionheater unit IS in those instances where a heat capacity is required iniexcess of the heat capacity capable of being produced by one unit, a plurality of the units may be used in a confined space by the arrangement of the units in a superposed relation. To, accomplish this superposed assembly of the units for independent operation, the fuel tank 98 is made with a transverse length or width substantially equalto the distance transversely porting member I1. supporting member I1 is spaced upwardly fromv ing unit 84 being controlled by the valve 31 pre- 1 viously mentioned.

In the operation of the heating is connected with a suitable source of power through either one of the socket connections I02 unit the motor and I83. The control switch 42 for the motor 3| is in a normally open position, which open position corresponds to a closed position of the valve 31 so that fuelis out off from-the mixing unit 34 concurrently with a stopping of the motor 3 I. On manipulation of the knob 38 to rotate the cam H for closing the switch 42, sufflcient lost motion is provided in the valve 31 so that the switch 42 is closed prior to any opening of the valve 31. A flow of air is thus initiated through the conditioning unit 34 prior to any admission of fuel thereto so as to provide for a scavenging action in the combustion chamber 48 before additional fuel is introduced therein.

Referring to the circuit diagram of Fig. 2 it is seen that the closing of the. switch 42 concurrently energizes the motor 3I and the resistance 9I which are connected in series. The sockets or receptacles I02 and I83 are connected to common lead wires I04 and I08, the use of a receptacle I82 and I83 being optional for a purpose to be later noted. To stop the operation of the heater the control knob 39 is reversely rotated to permit the switch 42 to return to an open position concurrently with a closing of the valve 31. Because of the previously noted lost motion in the valve 31 the fuel admitted into the combustion chamber 48 is stopped prior to the stopping of the motor 3|, to permit the sweeping of unburned fuel from the combustion chamber 48. There is thus provided a self-contained heating unit which requires for its complete operation only an electrical connection with a suitable source of electrical Because of the box-like construction of the between the flange portions 21 of the lower sup- As'previously mentioned the the lower end of the heating unit I5 so that on placing of one unit on top of another the flange portions 21 fit about the tank 93 to fix the relative positions of the units in a direction transversely thereof. The top of theframe member 23 (Fig. 3) is below the level of the top of the tank 98, with the bottom of the frame member extending downwardly to the bottom of the unit I5. Thus when the units I5 are arranged in a superposed relation the frame members 23 are arranged adjacent to each other and fix the relative longitudinal positions of the units. The units, therefore, are locked together by the mating engagement of the bottom portion of one with the tank 96 of another.

The use of air heating units for some applications has been somewhat curtailed because of such units generally requiring a substantially rigid supporting surface upon which they can be operated. This disadvantage has been particularly objectionable where air heating systems of this type are used in the heating of airplane engines for starting purposesij In planes, particularly of large type, the engines are located a considerable distance away from the ground, so that when-an air conduit is connected from a heating system on the ground to the engine much of the heating efliciency of .the heater is lost through such conduit connection. Thisloss of heat in the conduit connection necessitates a heating system having a capacity greater than would be required if the heat transmission losses were eliminated. This disadvantage has been overcome in the present invention by providing a heater which is light in weight, has a relatively large heat output and yet which is sufficiently stable to permit of its being operated while suspended from a single point thereon. In one commercialembodiment' of the invention the over-all length, width and height of-theunit I5 are about twelve inches, nine and one-quarter in'ches,and eight inches, respectively. This embodimenthas a weight of ap-{ proximately twenty-one pounds with the capacity of the fuel tank associated therewith being about I one and a quarter gallons. This capacity of the fuel tank provides in the neighborhood of ten hours of normal heater operation. The motor has a rating of about one-twentieth of a horse power with twelve volts and five amperes. The capacity of the air circulating fan is about twenty-five cubic feet per minute, with the unit having an output capacity of from about twelve to fifteen thousand B. t. u. per hour.. It is to be understood, of course, that the parts of the heat- 7 ing unit can be relatively changed within the scope of this invention to provide for fiexibility'in its application to different operating conditions.

In suspending the unit I5 there is provided,

means indicated generally as I01 including an eye stud I08 inserted through a tube I09 extended vertically through the gasoline tank 98 substantially centrally thereof. The stud I88 is anchored or threaded in a nut III connected to the 4. leg portion 22 of the connecting member IS. The tank 90 has a recessed portion 05 therein about the stud I08 so that the stud is below the level of the top of the tank The recess portion 85 is adapted to receive therein a chain link 050 connected in the eye of the stud I00. The link 95a is thus lifted from the recess when the unit is to be suspended or carried about, but is normally seated entirely within the recess 05 so as not to interfere with the vertical stacking of the units, as above described. The cap I for the fuel tank 00 is also inset for the same purpose. On suspending the unit I from the link "A, therefore, the entire weight of the unit is supported on the stud I08 and distributed substantially uniformly throughout the frame means I0. This manner of suspending the unit I5 is shown in Fig. 8 in connection with the heating of an airplane engine. An adjustable suspension strap 2 (Fig. 5) having a snap hook i I3 at each end thereof, is positioned about the propeller shaft II with the hooks I I3 connected with the link USA on the suspension menrber I00. As illustrated in Fig. 8 the airplane engine H0 is of the open face type, that is the engine cowl III extends about the engine rearwardly from the propeller I l0 and exposes the front of the engine H6 for direct cooling. With the unit I5 suspended directly from the propeller shaft and in front of the engine the heated air discharged from the outlet is passed directly within the cowl II I and about the engine H0.-

In actual practice a canvas covering indicated at I I8, is used to cover the exposed front portion of theengine, the heating unit being positioned on the outside of the covering with the outlet 48 pcsitioned at an opening in the covering. To facilitate the discharge of the heated air in a plurality of directions the outlet 89 is provided with an adjustable L-Joint H0 having a corrugated end I2I adapted to have a connecting hose stretched thereon when needed. Any directioning of the heated air is thus readily obtained by simply rotating the L-portion 9, and/or mtating the heating unit ,1! about its suspension point. I

As illustrated in Fig. 8 an electrical extension I22 is connected at one end with the receptacle I03 which is located at the bottom of the heating unit I5. The opposite end of the extension I22 may be connected with an engine-generator set indicated generally as I23. The selection of the receptacle I03 when the heating unit is operated in a suspended position provides for greater stability in retaining the unit It in a substantially horizontal position.

In.Fig. 9 the heating unit i5 is shown as applied to the heating of an airplane engine its located in the fuselage of the plane and rearwardly of the pilot's cockpit I28. The inlet I2! of the cooling air passage leading to the engine I28 is positioned to the rear and above the cockpit I26 so that suitable means for supporting the heater in a substantially horizontal position can 1 be readily provided. The supporting surface is positioned so that the heated air from the heating unit may be discharged directly into the inlet I27 to heat the engine I20. When the heating unit is operated in this position the plug or receptacle I02 is used for connection with the extension I22 leading to the engine-generator set I23, the receptacle I02 being located in the side of the unit I5. A receptacle I02 or I03, therefore, is readily accessible for operation of the heating unit in either a supported or suspended position, and in no way interferes with the vertical stacking of the units. It is to be understood of course that for multi-ensine planes a plurality of the heating units of this invention may be concurrently used and operated from a single-engine generator set so that all of the airplane 8 8 are heated together. In some instances it may be desirable to suspend a plurality of the units I5 in a stacked relation. The units in these cases are locked for movement together by locking means indicated generally as S, the sockets I02 being interconnected by an electrical harness H.

From a consideration of the above description and drawings, therefore, it is seen that the invention provides a self-contained heating unit of internal combustion type which is adapted to be operated simply by connecting it with a suitable source of electrical supply. This unit is small and compact, and of a construction such as to afford sufficient stability to retain it in a horizontal'positionwhen held suspended from a single point thereon. The arrangement of the fuel tank in a position above the combustion chamber provides for a gravity-feed system whereby the number of working parts requiring adjustment is appreciably reduced. The entire unit is completely assembled in package form, with the units so constructed that they may be stacked or superposed one on another in relative fixed positions' for independent operation. All of the working parts of the unit are arranged between two parallel vertically spaced horizontal plates, with the space therebetween being completely enclosed by a single housing member adapted to be slipped over the unit. Thus by simply removing the housing member all of the working parts are readily accessible. There are no parts having fine adjustments and since all of the working parts are completely enclosed the unit may be given considerable rough handling.

Although the invention has been described with specific reference to a preferred embodiment thereof it is to be understood that the parts thereof and their relative arrangement can be changed within the limits of this invention as defined by the appended claims.

I claim:

1. A heating unit of internal combustion type adapted to be suspended from one point in a substantially horizontal position, comprising frame means including a pair of horizontal supporting members, a vertical spacing member connecting said two supporting members and extending lonsitudinally of said unit, a-oombustion chamber on one side of said spacing member, means for suplying air to said combustion chamber, means for operating said air supply means, said air supply means and operating means being located on the opposite side of said spacing member, a fuel tank mounted on the upper one of said supporting members, suspension 'means extended vertically through said fuel tank, and means anchoring said suspension means with said frame means at said one point.

2. An air heating unit of internal combustion type adapted to be suspended from one point in a substantially horizontal position, including a pair of flat substantially rectangular frame members. a substantially vertical member for spacing said two frame members apart and connecting the same together, a combustion chamber located to oneside of said spacing member, means for supplying air to said combustion chamber, means for operating said air supply means, said operating means and air supply means being positioned to the other side of said spacing member stantially centrally of the fuel tank and extending vertically therethrough, and means securing said suspension member with said vertical spacing member.

3. A heating unit of internal combustion type adapted for suspension in a substantially horizontal position from a single point thereon comprising, housing means of a substantially rectangular shape, a vertical frame member extending longitudinally of said housing means and dividing the same into two compartments, a combustion chamber, a passage for air to be heated thermally related with said combustion chamber, said combustion chamber and air passage being located in one of said compartments, blower means for supplying air to said combustion chamber and for circulating air through said air passage, a motor for driving said blower means, with.

said blower means and motor being arranged in the other one of said compartments, a fuel tank superposed on said housing means, means fluid connecting said fuel tank with said combustionchamber, means mechanically" connecting together said fuel tank and housing means, and a suspension member located substantially centrally of said fuel tank and extending vertically therethrough for attachment with said frame means.

4. A heating unit of internal combustion type adapted to be suspended in a substantially horizontal position from a single point thereon comprising, frame means including a pair of flat horizontal members, a member for vertically spacing said fiat members having the end portions thereof connected with said flat members,

said spacing member extending longitudinally of said horizontal members, a housing member for closing the space between said two flat members, and a suspension member extending vertically through said fuel tank and substantially centrally thereof for attachment to said framemeans... I

5. An air heating unit of internal combustion type comprising, frame means including a pair of substantially rectangularly shaped horizontal plate members, a vertical member extending 1ongitudinally of said plate members retaining the same in a spaced paralle1 relation, an open rectangular housing member adapted to be positioned about said. plate members to close the space therebetween, a combustion chamber within said housing member located to one side ofsaid vertical member and having a passage for air to be heated thermally related therewith, means for supplying air to said combustion chamber and for circulating air through said passage, a motor for operating said air supply and circulating means, with said air supply and circulating means and motor being positioned within said housing member to theother side of said vertical member, a fuel tank superposed on said frame means and rigidly secured thereto, and means extending vertically through said fuel tank and substantially centrally thereof for attachment to said frame means providing for the 'liftingof said heating unit.

6. A portable air heating system comprised of an assembly of heating units .of internal combustion type, each of said units including frame means having a. pair of substantially rectangi1- larly shaped horizontal frame members, a vertical member extending longitudinally of said frame members retaining the same in a spaced parallel relation, a combustion chamber 'positioned to one side of said vertical member having a passage for air to be heated in thermal relation therewith, means for supplying air to said combustion chamber and for circulating air through said passage, a motor for driving said air supply and air circulating means, with said motor and air sup-- ply and air circulating means being located to the other side of said vertical member, a fuel tank of rectangular shape superposed on the upper one of 'said frame members, a rectangularly shaped open housing member adapted to be positioned about said frame members and fuel tank for enclosing the space between said two frame members, said housing member having a rim portion projecting downwardly beyond said lower frame member, and the top of said housing member extending upwardly below the level of the top of said fuel tank, with the fuel tankon one of said heating units being adapted to be received within the housing member rim portion of another of said heating units to provide for the vertical stacking of said heating units, and means connecting together adjacent ones of said units to provide for the carrying of said heating system as a package unit.

'7. A portable air heating unit of combustion type including housing means of substantially rectangular shape, a vertical frame member extending longitudinally of said housing means and dividing the same into two compartments, a combustion chamber, passage means about said combustion chamber for air to be heated, said combustion chamber and passage means being in one of said compartments, means for moving air to said combustion chamber and through said passage means, means for operating; said air moving means, fuel supply means, with said air moving means, operating means and fuel supply means being arranged in the other of said compartments laterally of said combustion chamber,

a fuel tank carried on one of the walls of said housing means and in a substantially covering relation with said one wall, and means providing for the carrying of said heating unit connected with said housing means.

8. A self-contained heating unit adapted to forma part'of multi-unit heating apparatus and comprising, in combination, a housing provided with sidewalls and including top and bottom walls set inwardly from the edges of said side walls to provide fuel tank receiving wells at the top and bottom of said housing, liquid fuel burning heat generating means including a plurality of component parts mounted within said housing, a flat fuel tank snugly fitting withinthe well provided at one side of said housing and ex- 

